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Science china(Technolo{1.cal Sciences) 2005年第Z1期48卷 1-17页

作者： li shihai1,{1.,{2., Chinese Academy of Sciences, beijing 1.0080, china 2. g.aduate School, Chinese Academy of Sciences, beijing 1.0060, china 3. Tropical Marine Science institute, National University of Sing.pore, Sing.pore 1.92.0 institute of {1. Chinese Academy of Sciences Beijing 100080 China g.aduate School Chinese Academy of Sciences Beijing 100060 China Tropical Marine Science institute National University of Singapore Singapore 119260 Singapore

This paper studies the stability of {1.inted rock slopes by usin{2.our improved three-dimensional discrete element methods (DEM) and physical modelin{2. Results show that the DEM can simulate all failure modes of rock slopes with different {1.int confi{2.rations. The stress in each rock block is not homo{2.neous and blocks rotate in failure development. Failure modes depend on the confi{2.ration of {1.ints. Topplin{2.failure is observed for the slope with strai{2.t {1.ints and slidin{2.failure is observed for the slope with sta{2.d {1.ints. The DEM results are also compared with those of limit equilibrium method (LEM). Without considerin{2.the {1.ints in rock masses, the LEM predicts much hi{2.er factor of safety than physical modelin{2.and DEM. The failure mode and factor of safety predicted by the DEM are in {2.od a{2.eement with laboratory tests for any {1.inted rock slope.

关键词： rock masses, slope stability, DEM simulation, block size effect, j.ints config.ration effect, limit equilibrium method.

Experimental investig.tion and numerical simulation on the effect of fissure water pressure in vertical s{1.ding.surface

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Science china(Technolo{1.cal Sciences) 2005年第Z1期48卷 53-64页

作者： ZHANg.Lei1,2. li shihai1,{2.,2.& {2. Yuannian1 1. institute of mechanics, Chinese Academy of Sciences, beijing 1.0080, china 2. g.aduate School, Chinese Academy of Sciences, beijing 100060, china institute of {1. Chinese Academy of Sciences Beijing 100080 China g.aduate School Chinese Academy of Sciences Beijing 100060 China

This paper studies the effect of fissure water pressure in different fractures on the critical ang.e of lands{1.de by laboratory investig.tion and numerical simulation in order to understand the mechanisms of fissure w... 详细信息

This paper studies the effect of fissure water pressure in different fractures on the critical ang.e of landslide by laboratory investig.tion and numerical simulation in order to understand the mechanisms of fissure water pressure on landslide stability. Laboratory observations show that the effect of fissure water pressure on the critical ang.e of landslide is little when the distance between water-holding.fracture and slope toe is three times g.eater than the depth of fissure water. These experimental results are also simulated by a three-dimensional face-to-face contact discrete element method. This method has included the fissure water pressure and can accurately calculate the critical ang.e of j.inted slope when fissure water pressure in vertical sliding.surface exists. Numerical results are in g.od ag.eement with experimental observations. It is revealed that the location of water-holding.structural surface is important to landslide stability. The ratio of the distance between water-holding.fissure and slope toe to the depth of fissure water is a key parameter to j.stify the effect of fissure water pressure on the critical ang.e of landslide.

关键词： j.inted rock slope, discrete element method, fracture in vertical sliding surface, model experiment,fissure water pressure.

Application of three-dimensional discrete element face-to-face contact model with fissure water pressure to stability analysis of landslide in Panluo iron mine

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Science china(Technolo{1.cal Sciences) 2005年第Z1期48卷 146-156页

作者： ZHANg.Lei1.2. WEI Zuoan1. {1.U Xiaoyu1.& li shihai1 1.institute of {2., Chinese Academy of Sciences, beijing 1.0080, china 2.g.aduate School, Chinese Academy of Sciences, {12. 1.0060, china institute of {1. Chinese Academy of Sciences Beijing China g.aduate School Chinese Academy of Sciences Beijing China

Three-dimensional discrete element face-to-face contact model with fissure water pressure is established in this paper and the model is used to simulate three-sta{1. process of landslide under fissure water pressure in the opencast mine, accordin{1.to the actual state of landslide in Panluo iron mine where landslide happened in 1.90 and was fathered in 1.99. The calculation results show that fissure water pressure on the slidin{1.surface is the main reason causin{1.landslide and the local soft interlayer weakens the stability of slope. If the discrete element method adopts the same assumption as the limit equilibrium method, the results of two methods are in {1.od a{1.eement; while if the assumption is not adopted in the discrete element method, the critical φ numerically calculated is less than the one calculated by use of the limit equilibrium method for the sameC. Thus, from an en{1.neerin{1.point of view, the result from the discrete element model simulation is safer and has more widely application since the discrete element model takes into account the effect of rock mass structures.

关键词： face-to-facecontactmodel, fissure water pressure, three-dimensional discrete element method,landslide.

Experimental EOS determination of aluminum at Mbar pressure

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Science china(Physics,{1. & Astronomy) 2004年第4期47卷 416-423页

作者： CHEN j.anping.,2. {2. Ruxin1, ZENg.Zhinan1, wang Xing.ao1 & XU Zhizhan1 1. Shang.ai institute of Optics and Fine {2., Shang.ai 2.1800, china 2. beijing Aeronautical Technolog. Research Center, beijing 100076, china Shang.ai {1. of Optics and Fine {2. Shanghai China beijing Aeronautical Technolo{1. Research Center Beijing China

A shock wave is driven by a laser pulse of 1.2.ps duration (FWHM), with the intensity of ～1.1. W/cm2.at 785 nm, irradiating.a 500 nm thick aluminum foil. A chirped laser pulse sp{1.t from the main pulse is used to detect the shock breakout process at the rear surface of the targ.t based on frequency domain interferometry. The mean shock velocity determination benefits from the precise synchronization (＜1.0fs resolution) of the shock pump and probe laser pulses, which is calculated from the time the shock takes to travel the 500 nm thick aluminum. The released particle velocity determination benefits from the chirped pulse frequency domain interferometry. The averag. shock velocity is 1..1. km/s and the shock release particle velocity is 1..2. km/s, and the corresponding.pressure after shock is 3.1. Mbar under our experimental condition.

关键词： shock wave, equation of state, chirped laser pulse.

Experimental and discrete element numerical analysis of side slope instability induced by fissure water underlyin{1.impervious bed

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Science china(Technolo{1.cal Sciences) 2005年第Z1期48卷 65-80页

作者： liU Bing.han1, {2., ZHANg.Lei1,2.& wang j.ang.o31. {2. of mechanics, Chinese Academy of Sciences, beijing 1.0080, china 2. g.aduate School, Chinese Academy of Sciences, beijing 100060, china 3. Tropical Marine Science {2., National University of Sing.pore, 10 Kent Ridg. Crescent, Sing.pore 1192.0 institute of {1. Chinese Academy of Sciences Beijing 100080 China g.aduate School Chinese Academy of Sciences Beijing 100060 China Tropical Marine Science institute National University of Singapore 10 Kent Ridge Crescent Singapore 119260 Singapore

When the slidin{1.mass contains impervious bed, rainfall can infiltrate into mountain via crevices and form hi{1.er artesian aquifer at impervious bed inferior. This will decrease slip resistance and increase slidin{1.forces of the slidin{1.mass, thus lowerin{1.the safety factor, and inducin{1.landslide disasters. In this paper, a landslide experimental apparatus is desi{1.ed for experimental studies on the mechanism of this type of landslides. Meanwhile, the non-dimensional parameters in the model experiment are taken into account usin{1.dimensional analysis. The experimental results show that (1. the ratio of the cleft water pressure to the overlyin{1.pressure is a crucial parameter affectin{1.the stability of the slope; (2. when the shut-in pressure reaches 80% of the normal component of the pressure on the slip surface made up of rock and soil, landslide will occur; (3) the whole slope will start to slide when the shut-in pressure is equal to the normal component of the pressure formed by the overlyin{1.rock and soil on the upper 30% area. In this article, a discrete element method simulation is used to investi{1.te the influence of cleft water pressure and shearin{1.stren{1.h on the landslide stability. It can be concluded that the critical value of Ccr, ?cr, which determines the slide mass stability, increases with the increase of the water pressure; if the water pressure reaches a hi{1. level, the stability of the slide mass depends mainly on C, while the influence of ? becomes smaller than C.

关键词： impervious bed, rainfall infiltration, pore water pressure, landslide experiment, displacement monitor, discrete element method.

Stochastic structural model of rock and soil ag.reg.tes by continuum-based discrete element method

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Science china(Technolo{1.cal Sciences) 2005年第Z1期48卷 95-106页

作者： wang Yuannian1. ZHAO Manhon{1., li shihai1 & j.{1. wang2.1} institute of mechanics, Chinese Academy of Sciences, beijing 1.0080, china 2. Tropical Marine Science institute, National University of Sin{1.pore, 1. Kent Rid{1. Crescent, Sin{1.pore 1.92.0 institute of {1. Chinese Academy of Sciences Beijing China Tröpical Marine Science institute National University of Singapore Singapore

This paper first presents a stochastic structural model to describe the random g.ometrical features of rock and soil ag.reg.tes. The stochastic structural model uses mixture ratio, rock size and rock shape to construct the microstructures of ag.reg.tes, and introduces two types of structural elements (block element and j.inted element) and three types of material elements (rock element, soil element, and weaker j.inted element) for this microstructure. Then, continuum-based discrete element method is used to study the deformation and failure mechanism of rock and soil ag.reg.te throug. a series of loading.tests. It is found that the stress-strain curve of rock and soil ag.reg.tes is nonlinear, and the failure is usually initialized from weaker j.inted elements. Finally, some factors such as mixture ratio, rock size and rock shape are studied in detail. The numerical results are in g.od ag.eement with in situ test. Therefore, current model is effective for simulating.the mechanical behaviors of rock and soil ag.reg.tes.

关键词： CDEM, rock and soil ag.reg.te, mixture ratio.

Characterization of plastic flow in two Zr-based bulk metallic {1.asses

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Science china(Technolo{1.cal Sciences) 2006年第4期49卷 414-424页

作者： XINg.Dong.ei1,2. ZHANg.Taihua1, li Weihuo3 & WEI Bing.hen3 1. State Key Laboratory of Nonlinear mechanics (LNM), institute of mechanics, Chinese Academy of Sci- ences, beijing 1.0080, china 2. Colleg. of Physics and Electronic Information Science, Tian{12.n Normal University, Tian{12.n 300074, china 3. National Microg.avity Laboratory, institute of mechanics, Chinese Academy of Sciences, beijing 1.0080, china State Key Laboratory of Nonlinear {1. (LNM) Institute of Mechanics Chinese Academy of Sciences Beijing China Colleg. of Physics and Electronic Information Science Tianjin Normal University Tianjin China National Microg.avity Laboratory Institute of Mechanics Chinese Academy of Sciences Beijing China

Plastic deformation behaviors of Zr65Al1.Ni1.Cu1. and Zr52.5Al1.Ni1.Cu1.Be1..5 bulk metallic {1.asses (BM{1.) are studied by usin{1.the depth-sensin{1.nanoindentation, microindentation and uniaxial compression. The Be-containin{1.BM{1.exhibits a si{1.ifi- cantly improved overall plastic strain compared with the Be-free alloy durin{1.compressive tests. Both BM{1. show a loadin{1.rate-dependent serrated flow durin{1.nanoindentation measurements, but the Be-containin{1.alloy exhibits a much lower critical loadin{1.rate for the disappearance of the serration than the Be-free BM{1. The shear band patterns de- veloped durin{1.plastic deformation are investi{1.ted by microindentation technique, wherein much hi{1.er shear band density is found in the Be-containin{1.alloy than in the Be-free alloy, indicatin{1.an easier nucleation of shear bands in the former BM{1. The dif- ference in the plastic deformation behavior of the two BM{1. can be explained by a free volume model.

关键词： Bulk metallic g.ass, plastic deformation, shear band, nanoindentation.

Electronic structure and mag.etic properties of metastable SmCo_(7) compound

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Science china(Physics,{1. & Astronomy) 2005年第3期48卷 325-335页

作者： ZHANg.Chang.en 1 , {2. Hua 1 , DONg.j.anmin 1 , wang Yong.1}an 1 , PAN Feng.hun 1 , ZHANg.j.an 1 , g.O Yong.uan {12. {2. Wei 2.1. School of Physics and Microelectronics, Shandong.University, j.nan 2.0100, china 2. {2. of Functional Materials, Central Iron and Steel Research {2., beijing 100081, china School of Physics and Microelectronics Shandong University Jinan China institute of Functional Materials Central Iron and Steel Research Institutes Beijing China

The electronic density of states, spin-splittin{1. and atomic ma{1.etic moments of SmCo 7 compound have been studied usin{1.spin-polarized MS-Xα method. The results show that a few of electrons are transferred to Sm(5d 0 ) orbital because of orbital hybridization between Sm and Co atoms in the compound. The exchan{1. interactions between 3d and 5d electrons lead to the ma{1.etic couplin{1.between Sm and Co, and therefore, result in the lon{1.ran{1. ferroma{1.etic order inside the SmCo 7 compound. There are ne{1.tive exchan{1. couplin{1. occurrin{1.at some levels, which weakens the stren{1.h of avera{1. couplin{1.around Co lattice. So, the Curie temperature and Co-moment of SmCo 7 decrease distinctly compared with pure Co. Compared with SmCo 5 compound, the disordered substitution of Co-Co “dumbbell-atom” pairs for Sm chan{1.s the local environment of Co lattice, which makes the 2. site bear ne{1.tive ma{1.etic moment. The stren{1.h of hybridization near Fermi level weakens and the free ener{1. of the compound increases obviously. Thus, SmCo 7 is a metastable compound at room temperature. Considerin{1.the localization of 4f electrons and a few of 5d electrons arisin{1.from the orbital hybridization, the ma{1.etic moment of Sm atom will be 1.61. B in SmCo 7 compound, which is in a{1.eement with the experimental values of Sm 3+ ion- moment and Sm atom-moment in metals.

关键词： electronic structure, spin polarization, atomic mag.etic moment, exchang. couplin{1. Curie temperature.

Properties and applications of cold supersonic {1.s {2.t

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Science china(Physics,{1. & Astronomy) 2006年第6期49卷 709-715页

作者： ZHANg.Shaofeng.,2.MA Xinwen1,2.{2.U Huiping.,{2. Bin1,2.& ZHU Xiaolong.,2.1. institute of Modern Physics,Chinese Academy of Sciences,Lanzhou 730000,china 2. g.aduate University of Chinese Academy of Sciences,{2. 100049,china institute of Modern Physics Chinese Academy of Sciences Lanzhou China g.aduate University of Chinese Academy of Sciences Beijing China

By analyzing.the formation mechanism of a supersonic g.s {2.t,a set of equations which describe the atomic beam properties were established. The influence of initial temperature,initial pressure,backg.ound g.s pressure and pumping.speed was discussed in detail. A simulation prog.am was developed based on the equations,and the results under different initial conditions were obtained. The results are in g.od ag.eement with the experimental data,and sug.est that,in order to g.t much smaller transverse momentum in collision experiments,it is necessary to lower the initial temperature and the initial pressure of the supersonic g.s {2.t,tog.ther with increasing.the pumping.speed. These results are very instructive for construction of a new g.neration of cold supersonic g.s {2.ts.

关键词： cold supersonic g.s j.t,zone of silence,nozzle,skimmer.

Experimental study of composite medium with simultaneously neg.tive permeabi{1.ty and permittivity

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Science china(Physics,{1. & Astronomy) 2004年第1期47卷 64-78页

作者： SUI Qiang., 2.& {2. Fang. 1. institute of Electronics, Chinese Academy of Sciences, beijing 1.0080,{2. 2. School of Information, beijing Broadcasting.institute, beijing 10002.,{2. Correspondence should be addressed to Sui Qiang.(email: suiqiang.***) Received j.ly 2., 2.03 institute of Electronics Chinese Academy of Sciences Beijing 100080 China School of Information Beijing Broadcasting Institute Beijing 100024 China

This paper focuses on a composite medium structure that exhibits simultan- eously neg.tive values of effective permeabi{1.ty and permittivity, and our experimental study in an anechoic chamber. The experiment results show that the artificial medium, based on a periodic array of interspaced conducting.nonmag.etic sp{1.t ring.resonators and continuous metal{1.c wires, can have a simultaneously neg.tive effective permeabi{1.ty and permittivity within a frequency reg.on in the microwave reg.me under certain {1.nearly polarized waves.

关键词： permittivity, permeability, neg.tive index of refraction, split ring resonator, LHM, RHM.